body {
  width: 100%; /* body的宽度与浏览器保持一致*/
  margin: 0 auto; /* 页面最大宽度是640px，如果在比较大的手机上显示，显示不完全，居中显示 */
  min-width: 320px; /* 目前市面上最小手机分辨率为320 */
  max-width: 640px; /*经过测量*/
  background: #fff;
  font-size: 14px;
  font-family: -apple-system, Helvetica, sans-serif;
  line-height: 1.5;
  color: #666;
}

ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.app {
  height: 45px;
  line-height: 45px;
  background-color: #333333;
}

.app li {
  float: left;
  color: #fff;
  text-align: center;
}
.app li:nth-child(1) {
  width: 8%;
}

.app li:nth-child(2) {
  width: 10%;
}
.app li:nth-child(3) {
  width: 57%;
}
.app li:nth-child(4) {
  width: 25%;
  background-color: #f00;
}

.app ul li:nth-child(1) img {
  width: 10px; /*图片大小固定死*/
}
.app ul li:nth-child(2) img {
  width: 30px;
  vertical-align: middle; /*文字和图片默认基线对齐，需要改为middle*/
}

.search-wrap {
  position: relative;
  height: 44px;
  overflow: hidden;
}

.search-btn {
  position: absolute;
  left: 0;
  top: 0;
  /* background-color: pink; */
  width: 40px;
  height: 44px;
}
.search-btn span {
  display: block;
  width: 20px;
  height: 18px;
  /* background-color: #f00; */
  background-image: url(../images/s-btn.png);
  background-size: 20px 18px;
  margin: 14px 0 0 15px;
}

.search-login {
  position: absolute;
  right: 0;
  top: 0;
  width: 40px;
  height: 44px;
  /* background-color: purple; */
  text-align: center;
  line-height: 44px;
  color: #fff;
}
.search {
  overflow: hidden;
  height: 30px;
  background-color: #fff;
  margin: 0 50px;
  border-radius: 15px;
  margin-top: 7px;
}
.search i.jd {
  position: relative;
  margin: 8px 8px 0 15px;
  display: block;
  width: 20px;
  height: 15px;
  /* background-color: #f00; */
  background-image: url(../images/jd.png);
  background-size: 20px 15px;
  float: left;
}
.search i.jd::after {
  content: '';
  position: absolute;
  border-right: 1px solid #ddd;
  top: 0;
  left: 26px;
  height: 16px;
}
.search .icon {
  float: left;
  /* background-color: pink; */
  display: block;
  width: 18px;
  height: 15px;
  background-image: url(../images/jd-sprites.png);
  background-position: -83px 0;
  background-size: 200px;
  margin: 8px 0 0 15px;
}

.slider img {
  width: 100%; /*图片本身比较大，所以需要设置一下*/
}

.search-wrap {
  position: fixed; /*相对定位改为固定定位*/
  /* left: 0;
  right: 0; */
  width: 100%;
  overflow: hidden;
  /* width: 100%; 增加宽度，加了固定定位的盒子必须要有宽度 */
  height: 44px;
  min-width: 320px; /*增加最大宽度，最小宽度*/
  max-width: 640px;
}

/* 品牌日 */

.brand {
  overflow: hidden;
  border-radius: 10px 0 0 10px;
}

.brand div {
  float: left;
  width: 33.33%;
}

.brand div img {
  width: 100%;
}

img {
    vertical-align: middle;
}